scholarly journals The Use of Galleria mellonella Larvae to Identify Novel Antimicrobial Agents against Fungal Species of Medical Interest

2018 ◽  
Vol 4 (3) ◽  
pp. 113 ◽  
Author(s):  
Kevin Kavanagh ◽  
Gerard Sheehan
Keyword(s):  
Fungal Pathogens ◽  
Antimicrobial Agents ◽  
Galleria Mellonella ◽  
Fungal Infections ◽  
Fungal Species ◽  
Molecular Techniques ◽  
Antifungal Drugs ◽  
Immune Priming ◽  
Greater Wax Moth

The immune system of insects and the innate immune response of mammals share many similarities and, as a result, insects may be used to assess the virulence of fungal pathogens and give results similar to those from mammals. Larvae of the greater wax moth Galleria mellonella are widely used in this capacity and also for assessing the toxicity and in vivo efficacy of antifungal drugs. G. mellonella larvae are easy to use, inexpensive to purchase and house, and have none of the legal/ethical restrictions that are associated with use of mammals. Larvae may be inoculated by intra-hemocoel injection or by force-feeding. Larvae can be used to assess the in vivo toxicity of antifungal drugs using a variety of cellular, proteomic, and molecular techniques. Larvae have also been used to identify the optimum combinations of antifungal drugs for use in the treatment of recalcitrant fungal infections in mammals. The introduction of foreign material into the hemocoel of larvae can induce an immune priming effect which may operate independently with the activity of the antifungal drug. Procedures to identify this effect and limit its action are required.

scholarly journals Galleria mellonella for the Evaluation of Antifungal Efficacy against Medically Important Fungi, a Narrative Review

2020 ◽  
Vol 8 (3) ◽  
pp. 390 ◽  
Author(s):  
Sana Jemel ◽  
Jacques Guillot ◽  
Kalthoum Kallel ◽  
Françoise Botterel ◽  
Eric Dannaoui
Keyword(s):  
Fungal Pathogens ◽  
Galleria Mellonella ◽  
Fungal Infections ◽  
Antifungal Susceptibility ◽  
Antifungal Drugs ◽  
New Drugs ◽  
Development Of Resistance ◽  
Antifungal Efficacy

The treatment of invasive fungal infections remains challenging and the emergence of new fungal pathogens as well as the development of resistance to the main antifungal drugs highlight the need for novel therapeutic strategies. Although in vitro antifungal susceptibility testing has come of age, the proper evaluation of therapeutic efficacy of current or new antifungals is dependent on the use of animal models. Mammalian models, particularly using rodents, are the cornerstone for evaluation of antifungal efficacy, but are limited by increased costs and ethical considerations. To circumvent these limitations, alternative invertebrate models, such as Galleria mellonella, have been developed. Larvae of G. mellonella have been widely used for testing virulence of fungi and more recently have proven useful for evaluation of antifungal efficacy. This model is suitable for infection by different fungal pathogens including yeasts (Candida, Cryptococcus, Trichosporon) and filamentous fungi (Aspergillus, Mucorales). Antifungal efficacy may be easily estimated by fungal burden or mortality rate in infected and treated larvae. The aim of the present review is to summarize the actual data about the use of G. mellonella for testing the in vivo efficacy of licensed antifungal drugs, new drugs, and combination therapies.

scholarly journals Galleria mellonella: The Versatile Host for Drug Discovery, In Vivo Toxicity Testing and Characterising Host-Pathogen Interactions

Antibiotics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1545
Author(s):  
Magdalena Piatek ◽  
Gerard Sheehan ◽  
Kevin Kavanagh
Keyword(s):  
Antimicrobial Agents ◽  
Galleria Mellonella ◽  
Toxicity Testing ◽  
In Vivo Model ◽  
Ethical Considerations ◽  
Food Preservatives ◽  
In Vivo Toxicity ◽  
Greater Wax Moth ◽  
Development Processes

Larvae of the greater wax moth, Galleria mellonella, are a convenient in vivo model for assessing the activity and toxicity of antimicrobial agents and for studying the immune response to pathogens and provide results similar to those from mammals. G. mellonella larvae are now widely used in academia and industry and their use can assist in the identification and evaluation of novel antimicrobial agents. Galleria larvae are inexpensive to purchase and house, easy to inoculate, generate results within 24–48 h and their use is not restricted by legal or ethical considerations. This review will highlight how Galleria larvae can be used to assess the efficacy of novel antimicrobial therapies (photodynamic therapy, phage therapy, metal-based drugs, triazole-amino acid hybrids) and for determining the in vivo toxicity of compounds (e.g., food preservatives, ionic liquids) and/or solvents (polysorbate 80). In addition, the disease development processes are associated with a variety of pathogens (e.g., Staphylococcus aureus, Listeria monocytogenes, Aspergillus fumigatus, Madurella mycotomatis) in mammals are also present in Galleria larvae thus providing a simple in vivo model for characterising disease progression. The use of Galleria larvae offers many advantages and can lead to an acceleration in the development of novel antimicrobials and may be a prerequisite to mammalian testing.

scholarly journals From Design to in Vivo Active Organometallic-Containing Antimycotic Agents

2020 ◽  
Author(s):  
Riccardo Rubbiani ◽  
Tobias Weil ◽  
Noemi Tocci ◽  
Luciano Mastrobuoni ◽  
Severin Jeger ◽  
...  
Keyword(s):  
Rational Design ◽  
Fungal Infections ◽  
Binding Mode ◽  
Fungal Species ◽  
Antifungal Drugs ◽  
Hospital Environment ◽  
Ros Generation ◽  
Mice Model

Fungal infections are an alarming global problem, most importantly for immunocompromised patients in a hospital environment. The appearance of multidrug resistance in several fungal species is a strong indication that alternative treatments are required. Azoles represent the mainstay of antifungal drugs, and their mode of action involves the binding mode of these molecules to the fungal lanosterol 14α-demethylase target enzyme. In this work, by rational design, we have prepared and characterized four novel organometallic derivatives of the frontline antifungal drug fluconazole (<b>1a-4a</b>). All compounds showed excellent <i>in vitro</i> activity against the yeast <i>C. robusta</i>, clearly surpassing the progenitor organic drug fluconazole. As anticipated, due to the presence of the ferrocenyl moiety in <b>1a-4a</b>, a modest increase in ROS generation was observed on <i>C. robusta</i> upon treatment. Very importantly, enzyme inhibition and chemogenetic profiling demonstrated that lanosterol 14α-demethylase was the main target of the most active compound of the series, (<i>N</i>-(ferrocenylmethyl)-2-(2,4-difluorophenyl)-2-hydroxy-N-methyl-3-(1H-1,2,4-triazol-1-yl)propan-1-aminium chloride, <b>2a</b>). Transmission electron microscopy (TEM) studies suggested that <b>2a</b> induced a loss in wall integrity as well as intracellular features ascribable to late apoptosis or necrosis. The impressive activity of <b>2a</b> was further confirmed on clinical isolates, where antimycotic potency up to 400 times higher than fluconazole was observed. Also, <b>2a </b>showed activity towards azole-resistant strains. This finding is very interesting since the target of <b>2a</b> is primarily the same as that of fluconazole, emphasizing the role played by the organometallic moiety. <i>In vivo</i> experiments conducted with <b>2a</b> at a dose of 10 mg/Kg in mice model of <i>Candida</i> infections, while not decreasing fungal burden in the kidney, reduced distal distribution to liver and brain and greatly improved the inflammatory pathology in the kidney and colon, compared to untreated mice.<br>

scholarly journals Alexidine dihydrochloride has broad spectrum a ctivities against diverse fungal pathogens

2018 ◽  
Author(s):  
Zeinab Mamouei ◽  
Abdullah Alqarihi ◽  
Shakti Singh ◽  
Shuying Xu ◽  
Michael K. Mansour ◽  
...  
Keyword(s):  
Mammalian Cell ◽  
Fungal Pathogens ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
Immunocompromised Patients ◽  
Drug Resistant ◽  
Cell Toxicity ◽  
Diverse Range ◽  
Mammalian Cell Toxicity

AbstractInvasive fungal infections due to Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans, constitute a substantial threat to hospitalized, immunocompromised patients. Further, the presence of drug-recalcitrant biofilms on medical devices, and emergence of drug-resistant fungi such as Candida auris, introduce treatment challenges with current antifungal drugs. Worse, currently there is no approved drug capable of obviating preformed biofilms which increases the chance of infection relapses. Here, we screened a small molecule Prestwick Chemical Library, consisting of 1200 FDA approved off-patent drugs, against C. albicans, C. auris and A. fumigatus, to identify those that inhibit growth of all three pathogens. Inhibitors were further prioritized for their potency against other fungal pathogens, and their ability to kill preformed biofilms. Our studies identified the bis-biguanide Alexidine dihydrochloride (AXD), as a drug with the highest antifungal and anti-biofilm activity against a diverse range of fungal pathogens. Finally, AXD significantly potentiated the efficacy of fluconazole against biofilms, displayed low mammalian cell toxicity, and eradicated biofilms growing in mice central venous catheters in vivo, highlighting its potential as a pan-antifungal drug.ImportanceThe prevalence of fungal infections has seen a rise in the past decades due to advances in modern medicine leading to an expanding population of device-associated and immunocompromised patients. Furthermore, the spectrum of pathogenic fungi has changed, with the emergence of multi-drug resistant strains such as C. auris. High mortality related to fungal infections point to major limitations of current antifungal therapy, and an unmet need for new antifungal drugs. We screened a library of repurposed FDA approved inhibitors to identify compounds with activities against a diverse range of fungi, in varied phases of growth. The assays identified Alexidine dihydrochloride (AXD) to have pronounced antifungal activity including against preformed biofilms, at concentrations lower than mammalian cell toxicity. AXD potentiated the activity of fluconazole and amphotericin B against Candida biofilms in vitro, and prevented biofilm growth in vivo. Thus AXD has the potential to be developed as a pan-antifungal, anti-biofilm drug.

scholarly journals From Design to in Vivo Active Organometallic-Containing Antimycotic Agents

2020 ◽  
Author(s):  
Riccardo Rubbiani ◽  
Tobias Weil ◽  
Noemi Tocci ◽  
Luciano Mastrobuoni ◽  
Severin Jeger ◽  
...  
Keyword(s):  
Rational Design ◽  
Fungal Infections ◽  
Binding Mode ◽  
Fungal Species ◽  
Antifungal Drugs ◽  
Hospital Environment ◽  
Ros Generation ◽  
Mice Model

Fungal infections are an alarming global problem, most importantly for immunocompromised patients in a hospital environment. The appearance of multidrug resistance in several fungal species is a strong indication that alternative treatments are required. Azoles represent the mainstay of antifungal drugs, and their mode of action involves the binding mode of these molecules to the fungal lanosterol 14α-demethylase target enzyme. In this work, by rational design, we have prepared and characterized four novel organometallic derivatives of the frontline antifungal drug fluconazole (<b>1a-4a</b>). All compounds showed excellent <i>in vitro</i> activity against the yeast <i>C. robusta</i>, clearly surpassing the progenitor organic drug fluconazole. As anticipated, due to the presence of the ferrocenyl moiety in <b>1a-4a</b>, a modest increase in ROS generation was observed on <i>C. robusta</i> upon treatment. Very importantly, enzyme inhibition and chemogenetic profiling demonstrated that lanosterol 14α-demethylase was the main target of the most active compound of the series, (<i>N</i>-(ferrocenylmethyl)-2-(2,4-difluorophenyl)-2-hydroxy-N-methyl-3-(1H-1,2,4-triazol-1-yl)propan-1-aminium chloride, <b>2a</b>). Transmission electron microscopy (TEM) studies suggested that <b>2a</b> induced a loss in wall integrity as well as intracellular features ascribable to late apoptosis or necrosis. The impressive activity of <b>2a</b> was further confirmed on clinical isolates, where antimycotic potency up to 400 times higher than fluconazole was observed. Also, <b>2a </b>showed activity towards azole-resistant strains. This finding is very interesting since the target of <b>2a</b> is primarily the same as that of fluconazole, emphasizing the role played by the organometallic moiety. <i>In vivo</i> experiments conducted with <b>2a</b> at a dose of 10 mg/Kg in mice model of <i>Candida</i> infections, while not decreasing fungal burden in the kidney, reduced distal distribution to liver and brain and greatly improved the inflammatory pathology in the kidney and colon, compared to untreated mice.<br>

scholarly journals Amphotericin B, the Wonder of Today’s Pharmacology Science: Persisting Usage for More Than Seven Decades

2020 ◽  
Author(s):  
Falah Hasan Obayes AL-Khikani
Keyword(s):  
Adverse Effects ◽  
Fungal Infection ◽  
Amphotericin B ◽  
Antimicrobial Agents ◽  
Fungal Infections ◽  
Wide Spectrum ◽  
Antifungal Drugs ◽  
Systemic Fungal Infection

Background: Despite several available topical and systemic antifungal drugs for the treatment of fungal infections, Amphotericin B (AmB) is still one of the most common first-line choices in treating systemic fungal infection for more than seven decades after its discovery.  Objectives: Amphotericin B which belongs to the polyene group has a wide spectrum of in vitro and in vivo antifungal activity. Its mechanism of antifungal action is characterized by creating a pore in the fungal plasma membrane leading to cell death. Methods: In addition to the old formula of deoxycholate-Amphotericin B (D-AmB), three lipid formulas have been developed to reduce the adverse effects of conventional AmB (D-AmB) in the human body and increase its therapeutic efficacy. All of the known available formulas of AmB are administrated via intravenous injection to treat severe systemic fungal infections, while the development of the topical formula of AmB is still under preliminary research. Numerous pharmaceutical formulas of systemic and topical applications with clinical uses of AmB in just humans, not in vitro or animals model, against various fungal infections are discussed in this review. Topical AmB formulas are a promising way to develop effective management and to reduce the adverse effects of intravenous formulas of AmB without laboratory monitoring. Results: The wonderful pharmacological properties of AmB with its prolonged use for about seven decades may help researchers to apply its unique features on other various antimicrobial agents by more understanding about the AmB mechanisms of actions. Conclusion: Amphotericin B is widely used intravenously for the treatment of systemic fungal infection, while the topical formula of AmB is still under experimental study. 

scholarly journals Alexidine Dihydrochloride Has Broad-Spectrum Activities against Diverse Fungal Pathogens

mSphere ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Zeinab Mamouei ◽  
Abdullah Alqarihi ◽  
Shakti Singh ◽  
Shuying Xu ◽  
Michael K. Mansour ◽  
...  
Keyword(s):  
Mammalian Cell ◽  
Fungal Pathogens ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
Immunocompromised Patients ◽  
Cell Toxicity ◽  
Diverse Range ◽  
Content Type ◽  
Mammalian Cell Toxicity

ABSTRACT Invasive fungal infections due to Candida albicans, Aspergillus fumigatus, and Cryptococcus neoformans constitute a substantial threat to hospitalized immunocompromised patients. Further, the presence of drug-recalcitrant biofilms on medical devices and emergence of drug-resistant fungi, such as Candida auris, introduce treatment challenges with current antifungal drugs. Worse, currently there is no approved drug capable of obviating preformed biofilms, which increase the chance of infection relapses. Here, we screened a small-molecule New Prestwick Chemical Library, consisting of 1,200 FDA-approved off-patent drugs against C. albicans, C. auris, and A. fumigatus, to identify those that inhibit growth of all three pathogens. Inhibitors were further prioritized for their potency against other fungal pathogens and their ability to kill preformed biofilms. Our studies identified the bis-biguanide alexidine dihydrochloride (AXD) as a drug with the highest antifungal and antibiofilm activity against a diverse range of fungal pathogens. Finally, AXD significantly potentiated the efficacy of fluconazole against biofilms, displayed low mammalian cell toxicity, and eradicated biofilms growing in mouse central venous catheters in vivo, highlighting its potential as a pan-antifungal drug. IMPORTANCE The prevalence of fungal infections has seen a rise in the past decades due to advances in modern medicine leading to an expanding population of device-associated and immunocompromised patients. Furthermore, the spectrum of pathogenic fungi has changed, with the emergence of multidrug-resistant strains such as C. auris. High mortality related to fungal infections points to major limitations of current antifungal therapy and an unmet need for new antifungal drugs. We screened a library of repurposed FDA-approved inhibitors to identify compounds with activities against a diverse range of fungi in varied phases of growth. The assays identified alexidine dihydrochloride (AXD) to have pronounced antifungal activity, including against preformed biofilms, at concentrations lower than mammalian cell toxicity. AXD potentiated the activity of fluconazole and amphotericin B against Candida biofilms in vitro and prevented biofilm growth in vivo. Thus, AXD has the potential to be developed as a pan-antifungal, antibiofilm drug.

scholarly journals Assessing the bioactive profile of anti-fungal loaded calcium sulfate against fungal biofilms

2021 ◽  
Author(s):  
Mark C. Butcher ◽  
Jason L. Brown ◽  
Donald Hansom ◽  
Rebecca Wilson-van Os ◽  
Craig Delury ◽  
...  
Keyword(s):  
Calcium Sulfate ◽  
Fungal Pathogens ◽  
Pathogenic Fungi ◽  
Fungal Species ◽  
Antifungal Drugs ◽  
Release Mechanism ◽  
Local Antibiotics ◽  
Biofilm Inhibition

Calcium sulfate (CS) has been used clinically as a bone or void filling biomaterial, and due to its resorptive properties have provided the prospect for its use as a release mechanism for local antibiotics to control biofilms. Here, we aimed to test CS beads loaded with three antifungal drugs against planktonic and sessile fungal species to assess whether these antifungal beads could be harnessed to provide consistent release of antifungals at biofilm inhibitive doses. A panel of different fungal species (n=15) were selected for planktonic broth microdilution testing with fluconazole (FLZ), amphotericin B (AMB) and caspofungin (CSP). After establishing planktonic inhibition, antifungal CS beads were introduced to fungal biofilms (n=5) to assess biofilm formation and cell viability through a combination of standard quantitative and qualitative biofilm assays. Inoculation of a hydrogel substrate, packed with antifungal CS beads, was also used to assess diffusion through a semi-dry material, to mimic active infection in-vivo. In general, antifungals released from CS loaded beads were all effective at inhibiting the pathogenic fungi over 7-days within standard MIC ranges for these fungi. We observed a significant reduction of pre-grown fungal biofilms across key fungal pathogens following treatment, with visually observable changes in cell morphology and biofilm coverage provided by scanning electron microscopy. Assessment of biofilm inhibition also revealed reductions in total and viable cells across all organisms tested. These data show that antifungal loaded CS beads produce a sustained antimicrobial effect, which inhibits and kills clinically relevant fungal species in-vitro as planktonic and biofilm cells.

scholarly journals The landscape of toxic intermediates in the metabolic networks of pathogenic fungi reveals targets for antifungal drugs

2021 ◽  
Author(s):  
Jan Ewald ◽  
Paul Mathias Jansen ◽  
Sascha Brunke ◽  
Davina Hiller ◽  
Christian H. Luther ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Metabolic Networks ◽  
Fungal Infections ◽  
Pathogenic Fungi ◽  
Acid Synthesis ◽  
Fungal Species ◽  
Antifungal Drugs ◽  
Random Forest Regression ◽  
Amino Acid Synthesis ◽  
Emergence Of Resistance

The burden of fungal infections for humans, animals and plants is widely underestimated and comprises deadly infections as well as great conomic costs. Despite that, antifungal drugs are scarce and emergence of resistance in fungal strains contributes to a high mortality. To overcome this shortage, we propose toxic intermediates and their controlling enzymes in metabolic pathways as a resource for new targets and provide a web-service, FunTox-Networks to explore the landscape of toxic intermediates in the metabolic networks of fungal pathogens. The toxicity of metabolites is predicted by a new random forest regression model and is available for over one hundred fungal species. Further, for major fungal pathogens, metabolic networks from the KEGG database were enriched with data of toxicity and regulatory effort for each enzyme to support identification of targets. We determined several toxic intermediates in fungal-specific pathways like amino acid synthesis, nitrogen and sulfur assimilation, and the glyoxylate bypass. For the latter, we show experimentally that growth of the pathogen Candida albicans is inhibited when the detoxifying enzymes Mls1 and Hbr2 are deleted and toxic glyoxylate accumulates in the cell. Thus, toxic pathway intermediates and their controlling enzymes represent an untapped resource of antifungal targets.

Transgenic expression of gallerimycin, a novel antifungal insect defensin from the greater wax moth Galleria mellonella, confers resistance to pathogenic fungi in tobacco

2006 ◽  
Vol 387 (5) ◽  
pp. 549-557 ◽  
Author(s):  
Gregor Langen ◽  
Jafargholi Imani ◽  
Boran Altincicek ◽  
Gernot Kieseritzky ◽  
Karl-Heinz Kogel ◽  
...  
Keyword(s):  
Transgenic Tobacco ◽  
Fungal Pathogens ◽  
Galleria Mellonella ◽  
Ectopic Expression ◽  
Pathogenic Fungi ◽  
Transgenic Expression ◽  
Greater Wax Moth ◽  
Insect Defensin ◽  
Wax Moth

Abstract A cDNA encoding gallerimycin, a novel antifungal peptide from the greater wax moth Galleria mellonella, was isolated from a cDNA library of genes expressed during innate immune response in the caterpillars. Upon ectopic expression of gallerimycin in tobacco, using Agrobacterium tumefaciens as a vector, gallerimycin conferred resistance to the fungal pathogens Erysiphe cichoracearum and Sclerotinia minor. Quantification of gallerimycin mRNA in transgenic tobacco by real-time PCR confirmed transgenic expression under control of the inducible mannopine synthase promoter. Leaf sap and intercellular washing fluid from transgenic tobacco inhibited in vitro germination and growth of the fungal pathogens, demonstrating that gallerimycin is secreted into intercellular spaces. The feasibility of the use of gallerimycin to counteract fungal diseases in crop plants is discussed.

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